1. Field of the Invention
The present invention relates to a method, system, and program for maintaining a namespace of filesets accessible to clients over a network.
2. Description of the Related Art
In a distributed file system, clients share a global namespace addressing storage locations on distributed storage devices. A central server manages the distributed file namespace for the clients. For instance, a metadata server cluster comprised of multiple server devices may maintain the global namespace of a distributed file system stored in different storage pools for the clients. The global namespace is organized into filesets, which comprise file system directories and folders accessible to the clients for file operations. On the clients, the global namespace appears as a hierarchical file directory provided by the operating system running on the client.
The metadata servers would create and manage filesets and define policy rules that determine in which storage pools files are stored. The metadata servers may manage a list of rules that are considered when creating a file. A rule condition may indicate a file type, fileset or client and an associated storage pool in which to create the file. The metadata server scans the list of rules to determine which rule applies to the file create request, i.e., which rule identifies the file type of the file request, the fileset in which the file is created and/or the client initiating the file request. If the rule condition is satisfied, then the file is created in the storage pool associated with the satisfied rule. Further details of a distributed file system using metadata servers is described in the International Business Machines Corporation (“IBM”) publication “IBM Total Storage: Introducing the SAN File System”, document no. SG24-7057-00 (November 2003), which publication is incorporated herein by reference in its entirety.